Improving Accuracy and Completeness in the Collaborative Staging System for Stomach Cancer in South Korea


Background: Cancer staging enables planning for the best treatments, evaluation of prognosis, and predictionsfor survival. The Collaborative Stage (CS) system makes it possible to significantly reduce the proportion ofpatients labeled at an “unknown” stage as well as discrepancies among different staging systems. This study aimsto analyze the factors that influence the accuracy and validity of CS data. Materials and
Methods: Data wererandomly selected (233 cases) from stomach cancer cases enrolled for CS survey at the Korea Central CancerRegistry. Two questionnaires were used to assess CS values for each case and to review the cancer registrationenvironment for each hospital. Data were analyzed in terms of the relationships between the time spent foracquisition and registration of CS information, environments relating to cancer registration in the hospitals,and document sources of CS information for each item.
Results: The time for extracting and registering datawas found to be shorter when the hospitals had prior experience gained from participating in a CS pilot studyand when they were equipped with full-time cancer registrars. Evaluation of the CS information according tomedical record sources found that the percentage of items missing for Site Specific Factor (SSF) was 30% higherthan for other CS variables. Errors in CS coding were found in variables such as “CS Extension,” “CS LymphNodes,” “CS Metastasis at Diagnosis,” and “SSF25 Involvement of Cardia and Distance from EsophagogastricJunction (EGJ).”
Conclusions: To build CS system data that are reliable for cancer registration and clinicalresearch, the following components are required: 1) training programs for medical records administrators; 2)supporting materials to promote active participation; and 3) format development to improve registration validity.